Leukapheresis and elutriation have been utilized in a tandem fashion to obtain up to 1 billion purified monocytes (in suspension) and 6 billion monocyte-depleted lymphocytes from a single normal human donor. Innovative elutriation techniques are now being developed to allow the purification of very large numbers of natural killer cells (NK), B cells, and T cell subsets (helper, suppressor and cytotoxic) for subsequent research investigations.